<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        /* <!-- float right会掉下去⚠ --> */

        .container {
            overflow: hidden;
        }

        .left,
        .right {
            width: 200px;
            float: left;
        }

        .right {
            float: right;
        }

        .center {
            /* 中间栏左右外边距为200px，以留出左侧栏和右侧栏的空间 */
            margin: 0 200px;
        }

        /* flex */

        .container {
            display: flex;
        }

        .left,
        .right {
            width: 200px;
        }

        .center {
            flex-grow: 1;
        }

        /* grid */
        .container {
            display: grid;
            grid-template-columns: 200px 1fr 200px;
        }

        .left {
            grid-column: 1;
        }

        .center {
            grid-column: 2;
        }

        .right {
            grid-column: 3;
        }

        /* grid */
        .container {
            display: grid;
            grid-template-areas: "lefta centera righta";
            grid-template-columns: 200px 1fr 200px;
        }

        .left {
            grid-area: lefta;
        }

        .center {
            grid-area: centera;
        }

        .right {
            grid-area: righta;
        }
    </style>
</head>

<body>
    <div class="container">
        <div class="left">Left</div>
        <div class="center">Center</div>
        <div class="right">Right</div>
    </div>

</body>

</html>